The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Optical lens based systems are the backbone for many commercial applications, e.g., imaging and directed illumination systems. At the heart of these systems is the lensing optical system. However, the optical performance of an optical lensing system is limited by fabrication capabilities. For example, the ability to image at once the sky hemi-sphere for astronomical applications, which require wide angle cameras (such as for virtual reality applications), or to project light from a planar emitter to the hemisphere or a selected area on the hemisphere for LIDAR (Light Detection and Ranging applications), are limited by lensing design and fabrication methods for manufacturing fish-eye lenses.
For a fish-eye lens that projects the hemi-sphere on the lower hemisphere of a Luneburg spherical lens, it was recently shown that the lens could be modified using transformation optics to project a sky hemi-sphere onto a plane (where a detector could be positioned at, for example). However, such a device requires a graded-index (GRIN) optics with large variations in index across the structure volume. This is problematic because present day fabrication processes for GRIN optics are limited in respect to the refractive index difference and spatial resolution, especially in the short wavelength range (i.e., near infra-red, visible, ultra-violet). Therefore, the performance of current technology implementation for the manufacture of GRIN optics prevents the use of such optics in important applications.